Structure P00060082+03731 · Cascade County, MT

US 87-us 89 over Box Elder Creek

Carries US 87-us 89 over Box Elder Creek, 8m SE Great Falls.

Overall conditionGood

Set by its lowest-rated component: Deck and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructure8/9 · Very Good
Substructuresets the rating7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT75 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9 · sets the ratingSuperstructure 8/9Substructure 7/9 · sets the rating

75 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built198937 years old
Length75.1 ft22.9 m
Daily traffic4,614counted 2023
Last inspectedMay 2023every 24 months

Location

StateMontana
CountyCascade
Location8m SE Great Falls
CarriesUS 87-us 89
CrossesBox Elder Creek
Coordinates47.45436, -111.06072

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length75.1 ft (22.9 m)
Max Span75.1 ft (22.9 m)
Deck Width42.3 ft (12.9 m)
Deck Area295.4 sq m
Main Spans1
Year Built1989

Traffic

Avg Daily Traffic4,614 (2023)
Truck Traffic12%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberP00060082+03731

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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